After burning off the organic matter in the material, what is left is ash. It is the amount of inorganic matter present in any material. If any substance is heated to its combustion point in the presence of an oxidizing agent, only ash remains. To assess the quality of a material, it is important to assess the presence of inorganic components. Different procedures are defined to measure the ash content in foods.
wet ash
dry ashing
low temperature ashing
Select the test method according to the application of the material, the requirements of the sample, and the specification of the sample. These testing procedures can also help you easily distinguish the minerals present.
In the food industry, in order to determine the quality of food, different tests are performed. Today, ash testing is catching on because it speaks volumes about quality. Minerals present in the material can also be assessed by this test. According to regulators, the acceptable ash content is up to 5%, which not only helps determine the age of food.
How to prepare samples?
In order to perform an ash test, the importance of sample preparation cannot be overstated. Food samples need to be in powder form. Any moisture that is present dries first and can cause spills during heating. Fatty food samples dry to retain moisture, preventing splashing. Another major concern is sample contamination due to the surrounding environment or the container used to hold the sample. Samples need to weigh between 1 and 10 grams.
Different methods of testing with a muffle furnace
Dry Ashing - In this process, the sample is burned out using a muffle furnace. The temperature of the chamber was maintained at approximately 50°C. 600°C. At this temperature, water evaporates from the sample and the remaining contents are burned off. During this process, most minerals are turned into phosphates, sulfates and oxides. Due to the presence of some volatile substances in the sample, the test results may not be accurate. This is why other test methods are available when materials such as lead, mercury and iron are present in the sample.
By taking advantage of technological advancements, smart analytical instruments are being introduced to the market that do not require the processing of samples prior to testing. They are equipped with decision-making circuits that first dry the moisture at a very high temperature range and then turn it into ash for analysis.
Wet Ashing – This technique for determining the ash content of a food sample is faster than other techniques. The time frame may vary from 10 minutes to several hours. During this process, the temperature range is set to 350°C.
The difference in weight before and after the test is the percentage of ash.
MASH = mass of ash sample,
MDRY = Refers to the mass of the dry sample.
MWET = Refers to the mass of the wet sample.
